Amazon Mechanical Turk is a service provided by Amazon.com of Seattle, Wash. Amazon Mechanical Turk provides the ability to submit tasks and have a human complete the task in exchange for a monetary reward for completing the task.
The Likert scale is a psychometric scale that allows respondents to specify their level of agreement with a particular statement (known as a Likert item) on a symmetric agreement-disagreement scale. A Likert item is simply a statement that the respondent is asked to evaluate according to any kind of subjective or objective criteria.